Cathodic Peak Research Articles

Synthesis, structural characterisations, electrochemical behavior and antibacterial activities of a chromium(III) resorcinolate complex

The integration and implementation of transition metal complexes as working electrode for surface modifications has become an area of research interest now a days. Based on this, a novel anionic complex having a formula of Na3[Cr(HR)4Cl2] (HR- = resorcinolate) with octahedral geometry, was prepared and characterized by elemental analysis, molar conductance, vibrational spectra. Electropolymerization of the ligand, salt, and complex was done on glassy carbon electrodes with effective surface area 0.15, 0.17, and 0.2 cm2 for poly(NaHR)/GCE, Cr(0)/GCE, and poly(Na3[Cr(HR)4(Cl2)]/GCE respectively. The presence of a redox polymer film on the surface of the electrode was indicated by the experimental changes observed for a solution containing Na3[Cr(HR)4Cl2]. Specifically, the anodic peak currents, which represent the oxidation process, showed significant increases at different potential values compared to the ligand and salt. These potential values were approximately + 114 mV and + 573 mV. Additionally, the cathodic peak current, which is corresponding to the reduction process, exhibited changes at − 230 mV as the scan cycles were increased. These variations strongly suggested the formation of a film composed of a redox polymer on the electrode's surface. Further, the resistance to charge transfer (Rct) of the compound is in the lower voltage compared to the free ligand, CrCl3•6H2O, and the unmodified GCE. This indicates that the modified compound exhibits improved conductivity due to its reduced charge transfer resistance. The antibacterial activity assessed against two Gram-positive bacteria strains (Staphylococcus aureus and Streptococcus epidermis) and two Gram-negative bacteria strains (Escherichia coli and Klebsiella pneumoniae), indicate that the Cr(III) complex exhibit higher antibacterial activity compared to the ligand and the metal salt but lower than the reference. The synthesized is a highly conductive material suitable for potential applications in sensors and catalysis, especially in situations that require efficient and rapid electron transfer process

Electronic Effect of the [Au(PPh3)]+ Fragment in the Stabilization of Imidazolium Salts and the Destabilization of NHCs

AbstractThis work presents the synthesis and characterization of mono‐ (1) and di‐nuclear (2) imidazolium salts stabilized by [AuPPh3]+ fragments. The presence of the gold moiety induces a significant decrease in the carbenic proton‘s acidic character (high pKa). This high stability is consistent with the pronounced instability of the conjugate bases obtained through deprotonation using strong bases. The formation of carbene species is accompanied by the identification of a 1,2‐rearrangement process in which a preference for the C‐bound species over the N‐bound species is observed. Experimental techniques such as NMR, single‐crystal X‐ray diffraction analysis, mass spectrometry, and computational calculations are employed to investigate the reactivity exhibited by the imidazolium salts. Additionally, the electrochemical properties of the two imidazolium salts were also investigated. This study reveals that both species 1 and 2 display two cathodic peaks which are related to two electro‐chemical irreversible reduction events. The results obtained from both experimental and theoretical studies of this system reveal a strong tendency of the [AuPPh3]+ fragment to stabilize imidazolium salts. Additionally, they demonstrate the preference of this fragment for C‐bound species over N‐bound ones, with the former proving to be highly unstable even under severe conditions of air and moisture exclusion.

Experimental investigation for in-situ hydrogen production by electrochemical reforming of glycerol

In this paper, hydrogen production from glycerol have been investigated in a cubic electrolysis cell with/without membrane and in the system with membrane electrode assembly (MEA). Membrane and electrode effects on hydrogen production were examined in the electrolysis cell originally designed and manufactured. A constant current density value of about 10 mA/cm2 was recorded in the electrochemical reforming of glycerol in acidic electrolyte conditions in the system using Nafion 117 membrane at room temperature under 2 V constant potential. The highest current density value was reached in the case where the oxidation of glycerol at the anode occurred on the Zn electrode and the hydrogen evolution reaction at the cathode occurred on the Pt electrode. The current density value increased by 24 % using a Pt electrode instead of Zn at the cathode. According to the results of the cathode peak area in the gas chromatography analysis, the highest hydrogen formation was recorded under these conditions. To create MEA, 5.7 mg/cm2 10 % Pt/C (0.57 mg/cm2 Pt) and 5 mg/cm2 Zn were loaded for the cathode and anode respectively. A nozzle-type current collector made of copper material was selected among the current collectors of different geometries and materials used in the electrochemical reforming of glycerol. A constant current density value of approximate 500 mA/cm2 was achieved under the specified conditions and with diverse system improvements.

Improved performance of Prussian blue solid contact allowing flow injection amperometric detection of potassium ions in the excess of sodium

Catalytically synthesized Prussian blue nanoparticles are a versatile solid contact for potassium and sodium ion-selective screen-printed electrodes. The cathodic peak current proportional to cation concentration was registered in flow injection amperometry regime. The ability of K+ to penetrate Prussian blue lattice resulted in 2–4-fold higher response to potassium ions relatively to sodium ions. Such intrinsic selectivity of Prussian blue to potassium provided an order of magnitude higher sensitivity of K+-selective electrodes in comparison to Na+-sensors, based on nanoparticles covered with the corresponding ion-selective membranes. In contrast to other known solid contacts, Prussian blue provides the highest sensitivity of potassium-selective electrodes in an amperometric regime (20–50 mA·cm−2·M−1). Moreover, 1 × 10-6 M is the lowest limit of detection ever achieved for Prussian blue-based ion-selective electrodes. The improved sensitivity and selectivity allowed flow injection amperometric detection of potassium ions in the presence of interfering ions. Despite K+ concentration is approximately 40-fold lower than Na+, sensors are applicable for detection of pathological and normal potassium and sodium ions in blood serum. The sensors designed in this work have opened a new opportunity for analyzing biological fluids with ion-selective electrodes in an amperometric regime.

Tailored Synthesis of CN-PPy Composite for Enhanced Electrochemical Functionality

This study details the synthesis of pure carbon nitride (CN) and composite polypyrrole through an in-situ polymerization method. The prepared samples were comprehensively characterized using Fourier Transform Infrared Spectroscopy (FT-IR), Field Emission Scanning Electron Microscopy (FESEM), and X-ray Diffraction (XRD). These analyses confirmed the chemical bonding, structural, and morphological characteristics of the products. Electrochemical measurements, conducted through cyclic voltammetry (CV) and Linear Sweep Voltammetry (LSV), revealed significant current rates in both anodic and cathodic peaks, indicating superior electrochemical properties. This work not only details the synthesis process but also provides a thorough understanding of the structural, morphological, and electrochemical aspects, exhibiting the materials’ potential for various applications in electrochemical devices.

Spectroscopic, electrochemical, and kinetic trends in Fe(III)–thiolate disproportionation near physiologic pH

In addition to its primary oxygen-atom-transfer function, cysteamine dioxygenase (ADO) exhibits a relatively understudied anaerobic disproportionation reaction (ADO-Fe(III)-SR → ADO-Fe(II) + ½ RSSR) with its native substrates. Inspired by ADO disproportionation reactivity, we employ [Fe(tacn)Cl3] (tacn = 1,4,7-triazacyclononane) as a precursor for generating Fe(III)–thiolate model complexes in buffered aqueous media. A series of Fe(III)–thiolate model complexes are generated in situ using aqueous [Fe(tacn)Cl3] and thiol-containing ligands cysteamine, penicillamine, mercaptopropionate, cysteine, cysteine methyl ester, N-acetylcysteine, and N-acetylcysteine methyl ester. We observe trends in UV–Vis and electron paramagnetic resonance (EPR) spectra, disproportionation rate constants, and cathodic peak potentials as a function of thiol ligand. These trends will be useful in rationalizing substrate-dependent Fe(III)–thiolate disproportionation reactions in metalloenzymes.Graphical abstract

Effect of cerium oxide nanorods growth time on the electrochromic properties of WO3/CeO2 hybrid films

In this study, the cerium oxide nanorods (CeO2) were grown on fluorine-doped tin oxide (FTO) glass substrates by using a hydrothermal process at growth times of 4hrs, 6hrs and 12hrs and annealed at temperature 3500C. The grown samples were characterized by using Scanning electron spectroscopy (SEM), Energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), Raman spectroscopy, and UV–Vis spectrometer. Tungsten oxide (WO3) film was deposited, on these hydrothermally grown nanorods (NRs), by using the DC sputtering process to develop WO3/CeO2 hybrid films. From the SEM and XRD analysis, CeO2 nanorods were observed at different growth times, and crystalline structures were observed respectively. The optical transmittance decreases with the increase in synthesis time, mainly due to the increase in nanorods' thickness. The diffusion coefficient of 11.24 × 10−11 cm2/s and the cathodic peak current of −10.1 mA was observed for 12-h WO3/CeO2 films and the coloration efficiency of 12 cm2/C was observed for 4-h WO3/CeO2 hybrid film.

Effectiveness of Cyclic Voltammetry in Evaluation of the Synergistic Effect of Phenolic and Amino Acids Compounds on Antioxidant Activity: Optimization of Electrochemical Parameters.

Antioxidant activity can be evaluated using cyclic voltammetry (CV). The aim of this work is to verify the efficacy of CV in evaluating the synergistic effect of bioactive compounds, such as phenolic and amino acid compounds, on antioxidant activity. Therefore, three types of model solutions were prepared: individual model solution (phenol and amino acid), (b) binary model solutions (phenol-phenol and amino acid-amino acid) and (c) mixed phenol-amino acid solutions. Electrochemical measurement conditions were optimized for phenolic compounds (pH 3.0, 1.0 g/L and 100 mV/s) and for amino acids (pH 7.0, 2.0 g/L for amino acids and 100 mV/s), and, for each solution, the functional groups responsible of the anodic and cathodic peaks were established. The peak anodic potential (Epa) and the onset potential (Eon) were two parameters of great importance. The first one was used to classify the solutions according to their antioxidant potential. In general, all the binary and mixed solutions had lower values of Epa than the corresponding individual model solution, which indicates an improvement in the antioxidant potential. The second one was used to evaluate the synergistic effects of phenolic compounds and amino acids.

Inherent D-A Architecture in Indoloquinoxalines with an Array of Substituents for Non-Volatile Memory Device Applications.

Donor-acceptor (D-A)-based architecture has been the key to increase storage capability efficiency through the enhanced charge transportation in the fabricated device. We have designed and synthesized a series of functionalized indoloquinoxalines (IQ) for non-volatile organic memory devices. The investigation on UV-visible spectra reveals the absorption maxima of the compounds around 420 nm, attributed to the intramolecular charge transfer between indole and quinoxaline moiety. The irreversible anodic peak in the 1.0 to 1.5 V range indicates the indole moiety's oxidation ability. Besides, the cathodic peak in the range of -0.5 to -1.0 V, contributed to the stability of the reduced quinoxaline unit. All the compounds exhibited uniformly covered thin film in SEM analysis, potentially facilitating the seamless charge carrier migration between adjacent molecules. The methoxyphenyl substituted compound exhibited the binary write-once read-many (WORM) memory behavior with the lowest threshold voltage of -0.81 V. The molecular simulations displayed the efficient intramolecular charge transfer, providing the fabricated device's distinctive conductive states. Except for the tert-butylphenyl compound, which showed volatile dynamic random-access memory (DRAM) behavior, all the other compounds exhibited non-volatile WORM memory behavior, suggesting IQs potential as an intrinsic D-A molecule in organic memory devices on further structural refinement.

Pyridine-assisted electrodeposition of Au(1 1 1)-dominant gold nanonetworks on glassy carbon electrode for anodic stripping voltammetry analysis of As(III), Se(IV) and Cu(II)

Gold nanonetworks with Au(111)-dominant facets (AuNNs(1 1 1)-D) modified glassy carbon electrode (GCE) was simply fabricated by electroreduction of Au(III) with the assistance of pyridine (Py). Cyclic voltammetry of Au(III)-Py complex exhibits two sequential cathodic peaks, reflecting the reduction of Au(III) to Au(I) intermediate and then to Au(0). The as-prepared AuNNs(111)-D/GCE was characterized by scanning electron microcopy, X-ray diffraction and electrochemistry methods, and the results showed that the gold crystalline spread out in a nanonetworks architecture with good distribution, high aspect-ratios, large roughness and 90 % Au(111) facets. The coordination effects of Py, the inferior affinity of Py on Au(111) facets and the sustained generation of Au(I) intermediate contributed to such gold nanoarchitecture. Differential pluse anodic stripping voltammetry analysis of As(III), Se(IV) and Cu(II) was performed on the AuNNs(1 1 1)-D/GCE with high performance. Sensitivity values of 16.9 µA μM−1 (As(III)), 9.51 µA μM−1 (Se(IV)), 6.09 µA μM−1 (Cu(II)), as well as limit of detection values of 0.67 nM (As(III)), 1.1 nM (Se(IV)), 0.53 nM (Cu(II)) were obtained (S/N = 3), respectively. The AuNNs(111)-D/GCE was used for As(III), Se(IV) and Cu(II) determination in real drinkable water samples with satisfied results.

Electrodeposition of Zn[sbnd]Co alloy coatings on carbon steel and their corrosion resistance

The development of ZnCo alloys appeared as alternative for obtaining layers more resistant than the conventional zinc with a minimum increment of cost. The aim of this work is to study the electrodeposition mechanism of the ZnCo alloy on SAE 1020 carbon steel by cyclic voltammetry using two baths with different [Zn2+]/[Co2+] concentration ratios and also to evaluate the corrosion resistance in 0.1 mol L−1 NaCl of electrodeposits obtained potentiostatically using electrochemical techniques as electrochemical impedance spectroscopy, linear polarization resistance and potentiodynamic polarization curves. The voltammograms showed two anodic peaks attributed to dissolution of zinc rich ƞ-phases and cobalt, and a cathodic peak related to ZnCo alloy deposition. The nucleation mechanisms were examined by fitting the experimental data (chronoamperometry) into the Scharifker and Hills nucleation models. Scanning electron microscopy (SEM) showed that the electrodeposits obtained for the [Zn2+]/[Co2+] 9:1 ratio presented a structure in the form of hexagonal platelets in comparison to the electrodeposits with [Zn2+]/[Co2+] 12:1 ratio, which presented cauliflower-shaped structures. On the other hand, the electrochemical techniques proved that the electrodeposits obtained for the [Zn2+]/[Co2+] 9:1 ratio at potential of −1450 mV presented the best anticorrosive properties. Structural and chemical characterization of coatings was accomplished by XRD and XRF.

Electrochemical Analysis for Total Alkalinity of Water by the Measurement of Cathodic Prepeak of Quinone Caused by Surplus Acid.

In this study, an electrochemical analysis, coupled with the concept of back neutralization titration and the voltammetric determination of surplus acid, is proposed for determining the total alkalinity of water samples. When linear sweep voltammetry of 3,5-di-tert-butyl-1,2-benzoquinone (DBBQ) with H2SO4 in a water and ethanol (44 : 56, v/v) mixture was carried out using a bare glassy carbon working electrode, a cathodic prepeak of DBBQ caused by H2SO4 was observed on the voltammogram at a more positive potential than when compared with the original cathodic peak of DBBQ. When similar voltammetry was carried out in the presence of Na2CO3 and H2SO4, the cathodic prepeak height of DBBQ was decreased with an increase in the Na2CO3 concentration. The decrease of the cathodic prepeak height of DBBQ was found to be linearly related to the Na2CO3 concentration ranging from 0.025 to 2.5 mM (r2 = 0.998). The total equivalent concentrations of inorganic bases in samples of mineral water and tap water were determined, and then the results were converted to the total alkalinities of the water samples (mg/L CaCO3). The total alkalinities of the water samples determined by the present electrochemical analysis were essentially the same compared with those by the neutralization titration method. From these results, we were able to demonstrate that the present electrochemical analysis with accuracy and precision could be applied to determine the total alkalinity, which is one of the indicators to examine water quality. The present electrochemical analysis would contribute to achieving the sustainable development goals (SDGs) of #6 and #14.

Cyclic Voltammetry Method for Analysis of Phosphate Concentration in Water

Phosphate is a nontoxic element but a limiting element for productivity. Several methods have been established to analyze the phosphate concentration in water. This study aims to analyze phosphate concentration in water using the voltammetry method using cyclic voltammetry. Cyclic voltammetry is an electroanalytical method that measures the current outcome of oxidation-reduction reactions in response to the potential. The current outcome is directly proportional to the phosphate concentration in the solution. The calibration curve was formed from the KH2PO4 standard solution using concentrations of 0.1 mg/L, 0.2 mg/L, 0.4 mg/L, 0.8 mg/L, and 1.6 mg/L. The voltammogram showed that the analyte does not have an anode peak current (Ipa), which means that the analyte solution did not have an oxidation reaction, so the cathode peak current (Ipc) value was used. Based on the calibration curve, the linear regression graph with a straight-line equation is y = -0,00000645632x - 0,000208737 with R2 of 0,99737. Meanwhile, this cyclic voltammetry method was validated by calculating the LOD and LOQ values; the results are 0.1034 mg/L and 0.3134 mg/L, respectively. Hence, based on the analysis of phosphate concentration in water samples, this method works satisfactorily and is suitable for routine analysis because of its advantages.

Voltammetric approach to measuring free acid in anhydride and ester based on benzoquinone electrochemical reduction

AbstractFree acids commonly exist in anhydride and esters because they are unstable and tend to break down into free acids, which affect the quality of subsequent products in industrial production. Phthalic anhydride and ethyl acetate undergo hydrolysis reactions to form phthalic acid and acetic acid. A differential pulse voltammetry method for the determination of phthalic acid and acetic acid was developed with a bare glassy carbon electrode. Phthalic acid and acetic acid caused a new cathodic peak at more positive potential during the reduction of 1,4‐benzoquinone in acetonitrile or aqueous solution. The new peaks are attributed to the drastic increase in pH at the electrode surface caused by the consumption of protons in the benzoquinone reduction reaction. The peak current of the new cathodic peak was dependent on the concentration of phthalic acid and acetic acid but independent of BQ, phthalic anhydride, and ethyl acetate. This method does not cause hydrolysis of anhydride and ester because no external base is introduced. Furthermore, the method is sensitive, rapid, and does not require pretreatment.

A highly sensitive electrochemical sensor for Cr6+ ions detection using Ag NPs/rGO/quercetin modified glassy carbon electrode for water applications

Heavy metals possess some serious hazardous influence on the environment as well as on human health. Monitoring of Cr6+ ions using the electrochemical sensing method proves to be an effective analytical tool and has an edge over the other conventional technologies. The glassy carbon electrode used in this study has its surface modified with highly sensitive silver nanoparticles, conductive 2-dimensional carbon material, and a metal chelating bio-compound prepared to significantly impact the selectivity and sensing of metal ions in the electrochemical determination. Applying the green chemistry principle, Graphene Oxide is reduced and functionalized simultaneously using a natural flavonoid called quercetin. Turkevich method was used to synthesis Silver nanoparticles. A novel composite is prepared by taking these compounds in a 1:1:2 ratio. The working electrode's surface was modified using this Ag NPs/Q-rGO composite and used in the analysis of Cr6+ ions. The physio-chemical characterization of the synthesized Ag NPs/quercetin-rGO composite was carried out. The surface morphology of the novel composite was observed. The cyclic voltammetry technique was used for electrochemical characterization. The monitoring of the Cr6+ metal ions using the Ag NPs/Q-rGO electrode was done with differential pulse voltammetry technique. The cyclic voltammogram for the Ag NPs/Q-rGO showed two anodic peaks at Epa1 = 0.28 V, Epa2 = 0.38 V, and one cathodic peak was seen at Epc = 0.14 V. Analytical parameters like the effect of electrolytes and the effect of pH were optimized. The results obtained from DPV experiments showed that the Ag NPs/Q-rGO electrode is efficient enough to sense the Cr6+ ions. Interpretation from the Linear plot helped in determining the LOD and LOQ of Cr6+ ions in the system which was found to be 0.07 μgL−1 and 0.224 μgL−1 respectively.

Zn–Cr pulse coatings for corrosion protection

ABSTRACT The influence of the Zn–Cr electrodeposition bath composition, cathode current density under direct current conditions, and the average pulse current density and the current density under pulse plating current conditions on the content of chromium in the obtained Zn–Cr coatings, the current efficiency and their corrosion properties were investigated. The obtained Zn–Cr coatings contained from about 0.01 wt-% to about 10 wt-%. The corrosion resistance largely depended on the chromium content of the coating, but also on the morphology and surface development. The best corrosion resistance was achieved for Zn–Cr alloy coatings obtained under impulse current conditions for average current densities 3 and 4 A dm−2, while cathodic peak current densities were 30 and 40 A dm−2.

A new strategy for the determination of dinobuton fungicide by square wave stripping voltammetry on the multi-walled carbon nanotube electrode

Dinobuton is a fungicide with a dinitrophenol group pesticide, and its electrochemical behavior was investigated by cyclic voltammetry (CV) and square wave stripping voltammetry (SWSV) on a multi-walled carbon nanotube paste electrode (MWCNTPE). First of all, optimum parameters such as pH, step potential, frequency, puls amplitude, deposition time and, deposition potential were specified by using SWSV on the MWCNTPE. In the negative potential scans, two cathodic peaks appeared at nearly −480 mV and –760 mV due to the nitro groups on the molecule and the second sharp one appeared at −760 mV (versus Ag/AgCl) was used for analytical purposes. The linear working range was found to be within 3.74–25.8 μM on the MWCNTPE by SWSV in pH 7.0 Britton Robinson (BR) buffer solution. The limit of detection (LOD) and limit of quantification (LOQ) values were found to be 0.73 μM and 2.43 μM, respectively. The interference study was conducted in the presence of some pesticides such as triasulfuron, azinphos-methyl, bromoxynil-octanoate, dialifos, fipronil, vinclozolin, iprodione, procymidone, and some selected metal ions withal. Furthermore, the proposed method was also applied to apple juice, tap water, and grape juice, and percent recoveries (%) were detected as 105.9 ± 4.3; 98.3 ± 0.9; 103.7 ± 2.5% with relative standard deviations of 4.0, 1.0, and 2.4%, respectively. On the other hand, percent relative errors were calculated as 5.90, 1.65, and 3.74%, respectively. High recoveries and low relative standard deviations indicate that the applicability of the proposed method in both matrix and real samples is satisfying.

Composition-dependent band structure parameters and band-gap bowing effect in a caesium lead mixed halide system: a cyclic voltammetry investigation.

Cyclic voltammetry techniques have been employed to study the effect of halide substitution on the band edge parameters and band gap bowing effect in the case of CsPbX3 [X = I, Br, Cl] perovskite nanocrystals (PNCs). A series of compositions, viz. CsPbI3, CsPb(I-Br)3, CsPbBr3, CsPb(Br-Cl)3 and CsPbCl3, have been prepared by a hot injection method. From powder XRD and HR-TEM analysis, the formation of a highly crystalline, cubic phase of the perovskite having size in the range from 7-20 nm has been confirmed. Sharp peaks in the photoluminescence spectra suggest the formation of quantum dots with narrow-size distribution. The composition-dependent optical band gap (εopgap) for CsPbX3 displays a systematic shift towards shorter wavelengths from I to Br to Cl substitutions. The cyclic voltammetry investigation on the dispersion of PNCs in nonaqueous solvents yielded prominent cathodic and anodic peaks. These are correlated to conduction (e1) and valence band edge (h1) positions, respectively. The h1 has been decreased substantially with I to Br to Cl in CsPbX3. Meanwhile, e1 shows a marginal increase. The values derived from CV data demonstrated an excellent match with UVPS results, reported for a similar system. From these results, the quasi-particle gap (εqpgap) and exciton binding energy have been estimated for all the compositions. The negative band gap bowing effect noted in these PNCs is attributed to the size quantization effect. The band-edge parameters reported in this work will be valuable in matching these heterojunctions with suitable electron/hole transport materials for optimum device-performance.

Fabrication and application of glutathione biosensing SPCE strips with gold nanoparticle modification.

Glutathione (GSH) is a major antioxidant in organisms. An alteration in GSH concentration has been implicated in a number of pathological conditions. Therefore, GSH sensing has become a critical issue. In this study, a disposable strip used for tyrosinase-modified electrochemical testing was fabricated for the detection of GSH levels in vivo. The system is based on tyrosinase as a biorecognition element and a screen-printed carbon electrode (SPCE) as an amperometric transducer. On the tyrosinase-SPCE strips, the oxidation reaction from catechol to o-quinone was catalyzed by tyrosinase. The tyrosinase-SPCE strips were modified with gold nanoparticles (AuNPs). In the presence of AuNPs of 25 nm diameter, the cathodic peak current of cyclic voltammetry (CV) was significantly enhanced by 5.2 fold. Under optimized conditions (250 μM catechol, 50 mM phosphate buffer, and pH 6.5), the linear response of the tyrosinase-SPCE strips ranged from 31.25 to 500 μM GSH, with a detection limit of approximately 35 μM (S/N > 3). The tyrosinase-SPCE strips have been used to detect real samples of plasma and tissue homogenates in a mouse experiment. The mice were orally administrated with N-acetylcysteine (NAC) 100 mg kg-1 once a day for 7 days; the plasma GSH significantly enhanced 2.8 fold as compared with saline-treated mice (1123 vs. 480 μM μg-1 protein). NAC administration also could alleviate the adverse effect of GSH reduction in the mice treated with doxorubicin.

Evaluating diverse electrode surface patterns of 3D printed carbon thermoplastic electrochemical sensors.

Electrochemical sensing techniques rely on redox reactions taking place at the electrode surface. The configuration of this surface is of the utmost importance in the advancement of electrochemical sensors. The majority of previous electrode manufacturing methods, including 3D printing have produced electrodes with flat surfaces. There is a distinct potential for 3D printing to create intricate and distinctive electrode surface shapes. In the proposed work, 3D printed carbon black polylactic acid electrodes with nine different surface morphologies were made. These were compared to a flat surface electrode. To evaluate the performance of the electrodes, measurements were conducted in three different redox probes (ferrocene methanol, ferricyanide, and dopamine). Our findings highlighted that when electrodes were normalised for the geometric surface area of the electrode, the surface pattern of the electrode surface can impact the observed current and electron transfer kinetics. Electrodes that had a dome and flag pattern on the electrode surface showed the highest oxidation currents and had lower values for the difference between the anodic and cathodic peak current (ΔE). However, designs with rings had lower current values and higher ΔE values. These differences are most likely due to variations in the accessibility of conductive sites on the electrode surface due to the varying surface roughness of different patterned designs. Our findings highlight that when making electrodes using 3D printing, surface patterning of the electrode surface can be used as an effective approach to enhance the performance of the sensor for varying applications.